97 chevrolet lumina ls 3.1 v6 P0420

i have had so many problems with this car. i just had the car tuned up with ac delco parts.before this i changed the egr valve and the intake manifold gaskets( and all related gaskets) about a day after I had the tune up done, the check engine light came on with a P0420 code. i am a financially challenged college student and this car is costing me a fortune. what is the cheapest way to troubleshoot this problem and is it going to cost me a lot to fix this? How quickly must i get this fixed?

Code PO420 designates ‘catalyst system efficiency below threshold’.

Codes do not pinpoint trouble locations but show the area of a fault.

This one may be telling you your catalytic converter is dying.

Try to get at least 2 opinions on this as these are expensive to replace. Like I said it MAY be the fault, so get it checked out.

thank you for telling me something i already knew. if you cant answer my question please do not reply.
my machine interprest the codes, but it give a variety of posibilities. the catalitic converter is
just one possibility. how do i figure out what this is. NO STUPID ANSWERS PLEASE.

With your attitude, who wants to help you? I don’t!

No wonder you are a challenged student.

Your name just went on the troll list.